Data transmission between terminals refers to: when data is transmitted between two or more terminals, the data may be subjected to various processing by a certain transmission protocol, such as format processing, packing or unpacking, and then the processed data is transmitted from a source terminal to a target terminal through one or more established transmission links. There are many kinds of ways to transmit data, for example, the terminals may transmit data through a network connection and instant messaging applications, and may also transmit data through Bluetooth®, infrared technology and so on. How to ensure that the data can be completely transmitted between two terminals during transmission process of various types of data becomes a hot issue in research.